Bicomponent Electrospinning of PVDF-Based Nanofiber Membranes for Air Filtration and Oil–Water Separation

Particulate matter (PM) and water pollution have posed serious hazards to human health. Nanofiber membranes (NFMs) have emerged as promising candidates for the elimination of PMs and the separation of oil-water mixtures. In this study, a polyvinylidene difluoride (PVDF)-based nanofiber membrane with an average diameter of approximately 150 nm was prepared via a double-nozzle electrospinning technology, demonstrating high-efficiency PM filtration and oil-water separation. The finer fiber diameter not only enhances PM filtration efficiency but also reduces air resistance. The high-voltage electric field and mechanical stretching during electrospinning promote high crystallization of β-phase PVDF. Additionally, the electrostatic charges generated on the surface of β-phase PVDF facilitate the adsorption of PM from the atmosphere. The introduction of polydopamine (PDA) in PVDF produces abundant adsorption sites, enabling outstanding filtration performance. PVDF-PVDF/PDA NFMs can achieve remarkable PM_0.3 filtration efficiency (99.967%) while maintaining a low pressure drop (144 Pa). PVDF-PVDF/PDA NFMs are hydrophobic, and its water contact angle (WCA) is 125.9°. It also shows excellent resistance to both acidic and alkaline environments, along with notable flame retardancy, as it can self-extinguish within 3 s. This nanofiber membrane holds significant promise for applications in personal protection, indoor air filtration, oily wastewater treatment, and environmental protection.